C-21 Learjet

The Learjet Model 35 and Model 36 are a group of American multi-role business jets and military transport aircraft. When used by the United States Air Force they carry the designation C-21A).

The aircraft are powered by two Garrett TFE731-2 turbofan engines. Its cabin can be arranged for 6-8 passengers. The Model 36 has a shortened passenger area in the fuselage, in order to provide more space in the aft fuselage for fuel tanks. It is designed for longer-range mission capability.

The engines are mounted in nacelles on the sides of the aft fuselage. The wings are equipped with single-slotted flaps. The wingtip fuel tanks distinguish the design from other aircraft having similar functions.

Development[]

The concept which became the LJ35 began as the Learjet 25BGF (with GF referring to "Garrett Fan"), a Learjet 25 with a then-new TFE731 turbofan engine mounted on the left side in place of the 25's General Electric CJ610 turbojet engine. This testbed aircraft first flew in May, 1971.^[1] As a result of the increased power and reduced noise of the new engine, Learjet further improved the design, and instead of being simply a variant of the 25, it became its own model, the 35.

Operational History[]

In 1976 American professional golfer Arnold Palmer used a Learjet 36 to establish a new round-the-world class record of 22,894 miles (36990 km) completed in 57 hours 25 minutes 42 seconds.

Production on the 35/36 series ceased in 1994.^[2]

As of January, 2007, the U.S. National Transportation Safety Board database^[3] lists 19 fatal accidents for the 35/35A, and two for the 36/36A.

Variants[]

35[]

The original Model 35 was powered by two TFE731-2-2A engines and was 13 inches longer than its predecessor, the Model 25. First flight of the prototype Model 35 was on August 22, 1973, and the aircraft was FAA certified in July, 1974. It could carry up to eight passengers. There were 64 base-model 35s built.^[2]

35A[]

The Model 35A is an upgraded Model 35 with TFE731-2-2B engines and a range of 2,789 miles, with a fuel capacity of 931 US gallons (3,524 L) with refueling accomplished at ground level through each wingtip tank. It was introduced in 1976, replacing the 35. Over 600 35As were built, with a production line that ended with serial number 677, in 1993.^[2]

C-21A[]

The C-21A is a military variant of the Learjet 35A, with room for eight passengers and 42 ft³ (1.26 m³) of cargo. In addition to its normal role, the aircraft is capable of transporting litters during medical evacuations.

Delivery of the C-21A fleet began in April 1984 and was completed in October 1985. Dyncorp International provides full contractor logistics support at seven worldwide locations.

There are 38 Air Force active duty aircraft, and 18 Air National Guard aircraft in the C-21A fleet. On April 1, 1997, all continental U.S.-based C-21As were realigned under Air Mobility Command, with the 375th Airlift Wing at Scott Air Force Base, Illinois, as the lead command. C-21As stationed outside the continental United States are assigned to the theater commanders.^[4]

36[]

The Model 36 is essentially identical to the 35, except that it has a larger fuselage fuel tank, giving it 500 miles longer range, but reducing the passenger area's length by 18 inches (0.46 m). It was certified, along with the 35, in July, 1974.

36A[]

Like the 35A, the Model 36A has upgraded engines and a higher maximum gross weight. It was introduced in 1976, replacing the 36.^[2]

Notable accidents and incidents[]

An Argentinian Air Force Learjet 35 was shot down by British forces during the 1982 Falklands War.[verification needed]

The 1996 New Hampshire Learjet crash on Christmas Eve, December 24, 1996, in which a Learjet 35A crashed in New Hampshire, leading to the longest missing aircraft search in that state's history, lasting almost three years, and eventually resulted in Congressional legislation mandating improved emergency locator transmitters (ELTs) be installed in U.S.-registered business jets.

On August 29, 1999, a U.S. registered Learjet 35A owned by Corporate Jets, Inc., was shot down near Adwa, Ethiopia, while flying from Luxor, Egypt, to Nairobi, Kenya, with the loss of three persons.^[5]

On October 25, 1999, professional golfer Payne Stewart was killed in the crash of a Learjet 35. The plane suffered a sudden loss of cabin pressure early in the flight due to a failure in the baggage compartment floor. All on board died of hypoxia, lack of oxygen, theorized due to a mis-labled oxygen tank on/off valve. The plane, apparently still on autopilot, continued flying until it ran out of fuel and crashed near Aberdeen, South Dakota after an uncontrolled descent.^[6]

On May 2, 2000, F1 race driver David Coulthard survived a Learjet 35 crash. His chartered aircraft was travelling from Farnborough Airfield to Côte d'Azur International Airport when it developed engine trouble, and crashed while making an emergency landing at Saint-Exupéry International Airport near Lyon, France. While Coulthard received only minor injuries, the front of the aircraft disintegrated upon impact, killing both pilots.

On June 2, 2006 a Learjet 35 registered to Christian televangelist Pat Robertson crashed a half-mile short of the runway at Groton-New London Airport in Groton, Connecticut. Both pilots were killed; however, the three passengers aboard escaped without injury. Robertson was not aboard the plane.

On November 4, 2007, a Learjet 35A crashed in São Paulo, Brazil, after a failed takeoff attempt. It destroyed a house in a residential area near the Campo de Marte Airport, killing the pilot, co-pilot and 6 people of the same family who were in the house.^[7]

Specifications (C-21A)[]

References[]

External links[]

Detailed NTSB slide presentation of results of the Payne Stewart crash